Events & Seminars

Six students Jyoti Rathore (14040), Anirudh Sharma (14011) of VII Sem; Sachin Solanki (15086), Sandeep (15094) of V Sem; and Shubham Chhabra (16150), Ambar Kumar (16016) of III Sem from Department of Computer Science and Engineeringrepresented Dronacharya College of Engineering, Gurgaon an event: “Talk by Dr. Neelesh B. Mehta”, on “Revisiting Amplify-and-Forward Relaying in Cooperative Communications and Underlay Cognitive Radio” organized by IEEE Communications Society (ComSoc), Delhi Chapter on September 09, 2014 at IIT Delhi.

Dr. Neelesh B. Mehta, the speaker is an Associate Professor in the Dept. of Electrical Communication Engineering at the Indian Institute of Science (IISc), Bangalore. Before joining IISc, he was a research scientist in USA from 2001 to 2007 in AT&T Laboratories, NJ, Broadcom Corp., NJ, and Mitsubishi Electric Research Laboratories (MERL), MA. He currently serves as an Executive Editor of the IEEE Transactions on Wireless Communications, and an Editor for the IEEE Transactions on Communications and the IEEE Wireless Communications Letters. He also serves as a Member-at-Large on the Board of Governors of the IEEE Communications Society.

The Highlight of the lecture was Relay-assisted cooperative communications, described as an appealing technology for next generation wireless systems as it exploits spatial diversity to combat wireless fading. AF relaying is considered to be simple to implement since the relay does not need to decode the received signal. While different variants of AF relaying have been extensively investigated in the literature, this talk suggested that they are ad hoc and sub-optimal as they restrict the relay’s gain or transmit power. He generalized the above policy applying it to underlay cognitive radio, which is a mode of access that promises to ease the severe spectrum crunch currently faced by wireless systems. 

The Speaker presented a summation about optimal relay gain and transmits power adaptation policies of Cooperative systems and Underlay CR systems. He described that tractable and implementable closed form bounds exist, being quite different from ad hoc policies used in literature. He also talked about near-optimal, simpler relay gain adaptation policies that are easier to implement and that provide valuable insights about the optimal policies. He demonstrated that the proposed policies require 2.0-7.7 dB lower SNRs than the conventional fixed-power and fixed-gain AF relaying policies. This translates into significant energy savings at the source and the relay, and motivates their use in cooperative and underlay cognitive radio networks. In the end, he highlighted how significant power saving was achieved using amplify and forward relaying in communication.

The talk concluded with an interactive session where Q&A round taking all the queries of the attendees and was a scholarly experience for all the attendees.

Some Glimpse: